Significant efforts have been made to produce porous polymeric materials to improve the use of natural resources and reduction of the carbon footprint in finished products. A typical approach to initiating pore formation in polymeric materials is by foaming the polymer using physical or chemical blowing agents, which create gas-filled pores though the bulk. Chemical blowing agents are compounds that undergo chemical reaction liberating gas that creates the pore structure through the bulk of the polymer. Physical blowing agents are typically compressed gases that are dispersed in the polymer and expand creating the pores. Regardless, typical foaming processes induce low molecular orientation because the pore formation happens when the polymer is in the molten state. This reduces the melt strength, thus leading to breaks in high speed production processes with high deformation rates (e.g., fiber spinning, film formation, molding, etc.). Another problem with such materials is that, even if they can be successfully manufactured, they tend to be stiff and thus difficult to manipulate into different shapes during use of the material.
As such, a need currently exists for an improved technique for creating pores in polymeric materials.